A class \(\mathcal {S}\)  of graphs (or binary relational structures) is small
if there exists \(c\)  such that \(\mathcal {S}\)  contains at most \(c^n \cdot n!\)  structures on the vertex set \([n]\) .
For instance, the class of trees is small, and more generally strict minor closed classes of graphs
are small as shown by Norine et al. [1]}.
It was shown in [2]} that classes with bounded twin-width are small.
